1. Technical Field
This invention relates to molding techniques, and more particularly to a technique for blow molding a tubular metal part to cause the part to assume a desired shape along at least a portion of the length of the part.
2. Discussion
Various molding techniques are used in a wide variety of applications to form various components, most typically from plastics. One common technique is known in the art as injection molding. With injection molding, a quantity of molten plastic is injected into a mold under pressure. The molten plastic is then allowed to cool. When removed from the mold, the plastic will have assumed the shape of the cavity of the mold.
While molding techniques such as injection molding have proved to be valuable in forming a wide variety of components, until the present time there has been no means for modifying the shape of existing tubular components through conventional molding techniques. Accordingly, up until the present time it has not been possible to take, for example, a tubular, extruded length of metal such as aluminum and form a portion of the metal into an enlarged shape. More specifically, it has not been possible to take a tubular, extruded length of aluminum, which is to form a component of a vehicle article carrier, and to mold the aluminum via the use of a heated molding tool and a pressurized gas such that a portion is enlarged in the shape of an end support. Such a process would permit elongated, tubular lengths of metal such as aluminum to be molded into various complex shapes.
It is therefore a principal object of the present invention to provide a molding process by which a tubular length of material such as aluminum can be modified such that one or more portions of the length of aluminum are formed into a desired, complex shape.
It is still another object of the present invention to provide a method of molding by which a length of tubular metal material such as aluminum may have one or more portions of its length modified to a desired complex shape, without affecting other portions of the length of material which do not need to be modified in shape.
It is still another object of the present invention to provide a method of molding by which a length of elongated, metal material may be quickly and easily inserted into a molding tool which causes one or more portions of the length of material to be enlarged into a desired shape without the need to perform numerous steps in the molding process.